Method of making chain links



Feb. 9, 1937.

I F. E. STAHL METHOD OF MAKING CHAIN LINKS Filed July 11, 1935 2 Sheets-Sheet 2 Even-L 07; FRANK E. STAHL Patented Feb. 9, 1937 UNITED STATES PATENT OFFICE METHOD OF MAKING CHAIN LINKS Application July 11, 1935, Serial No. 30,857

7 Claims.

My method relates in general to the manufacture of chain links, and particularly to the manufacture of links used in rotary kilns.

It is well known to those skilled in the art that in the use of rotary kilns for treating slurry, it is desirable that the chains used present as much exterior surface as is possible. To this end links are used which are deformed so as to make it possible to increase the number of links in a given length of chain and thereby present greater chain surface area to the slurry.

The object of the present invention is to provide a method of manufacturing links for such chains which is simple and economical. In order to manufacture a link of the above mentioned type, and to carry out the object of my invention, I show in the accompanying drawings, which form a part of this application, fragmentary portions of one form of apparatus for carrying out the invention, it being obvious that other forms of apparatus may be used for accomplishing substantially the same results. In the drawings:

Fig. 1 is a side elevation of a chain link of the ordinary type before being acted upon in accordance with my method.

Fig. 2 is a similar view showing the link in the course of its manufacture.

Fig. 3 is a similar View of my completed link.

Fig. 4 is a fragmentary, sectional, plan View of a portion of the apparatus for carrying out one step of my process.

Fig. 5 is a fragmentary, transverse, sectional elevation of other portions of the apparatus.

Fig. 6 is a fragmentary end view of further portions of apparatus for carrying out my invention.

Fig. '7 is an enlarged, face View of the bending tool used in carrying out my method.

Fig. 8 is a side elevation of the same.

Referring to Figs. 2, 3, and 5, where I show the links which are made in accordance with my process, the link, before being acted upon by the process, is of the conventional type having curved ends I0 and two substantially straight sides ll joining the curved ends, as shown in Fig. 1. In the process of manufacture, the straight sides I l are heated and pressed inwardly by suitable ap- 50 paratus to form the inwardly bent sides l2. It will be obvious, therefore, that by bending the sides inwardly, the link is somewhat shortened while maintaining the same surface area as that of the blank shown in Fig. 1, whereby a greater number of links may be used in a given length of chain, thus increasing the chain surface area for contact with the slurry.

In carrying out my method with the larger sized links, it is, of course, necessary that the portion to be bent be heated in order that the metal may 5 be conveniently bent and in order that the bend be localized. This heating may be accomplished in any one of a number of desired ways, but I have found it most practical to use electricity. In Figs. 4 and 5, I show fragmentary portions of means whereby the sides I I of the link blank may be heated. These means comprise two oppositely arranged positive electrodes I5 and two oppositely arranged negative electrodes l6, thus providing two pairs of electrodes, one on each side of the link blank. The pairs of electrodes, as shown in Fig. 4, are also spaced as to heat the desired length of straight side II when current is applied. The electrodes I5 and I6 are carried by suitable electrode holders l8 and I9 which are, of course, actuated by suitable means (not shown) to bring the electrodes into contact with the link blank when it is to be heated and to retract such electrodes from the link so that the same may be released when they have performed their function. Also shown in Fig. 4 are two oppositely arranged holding plungers I! which are brought into engagement with the blank by suitable apparatus (not shown) in timed relation with the actuation of electrodes [5 and I6 so as to centralize the blank and to hold it while it is being acted upon in accordance with my invention.

In Fig. 5, which shows in fragmentary manner some of the parts shown in Fig. 4, I also show a feed wheel 20 around which the chain 2| is passed. It is obvious that while I show in Figs. 1 to 3 individual chain links, this is, of course, for clearness of illustration and in the actual manufacture of these links they are engaged with each other in the form of a chain 2|, as shown in Fig. 5. This chain is threaded through the machine (not shown) and engages with the parts shown in fragmentary manner in Figs. 4 and 5, so that the straight sides ll of the links may be acted upon in accordance with my invention. In Fig. 5, the feed wheel 20 is actuated periodically by suitable means (not shown) to carry each alternate link into the position shown by link 22. In such position, as hereinbefore described, it will be held by the holding plungers l1 and the electrodes [5 and IE will be brought into contact therewith while being so held. In this figure, the links 23 and 22 have been partly 55 acted upon and the link 24 has been completely acted upon.

In Figs. '7 and 8, I show one form of bending tool 25 which may be used in carrying out my method. As particularly shown in Fig. 7, the outer working end of the tool is bifurcated, thus providing a working surface 26 which is formed by the body of the tool 25 and by the two side members 21. As viewed in Fig. '7, this tool is so proportioned that the curvature at the bottom of the side portions 21 will fit the transverse sectional curvature of the straight side ll of the chain link. The surface 26 as viewed from the side, as in Fig. 8, is also curved at such a radius that it will produce the curvature of the bent side l2 of the finished link.

The bending tool is positioned above' the portion of the sides ll of the link when held in position by means of the holding plungers and electrodes l5 and I6, as shown in Fig. 7, and it is provided with suitable means for causing it to reciprocate vertically. These means may be of any suitable typebut for convenience I have shown a plunger 30 mounted for vertical reciprocation in a guide block 3|. This guide block is suitably carried in a stationary manner by any part of the apparatus, and the plunger is actuated;.by means of a rocker arm 32. The rocker arm is controlled by suitable cam means (not shown) but so timed in relation to the actuation of the electrodes l5 and I6, the holding plunger I1, andthe feed wheel 20, that the bending tool will be brought into engagement with the side I I of thelink after the same has been sufliciently heated. It is obvious that the bending tool is so proportioned that when it is brought into engagement with the heated straight side H of the link to form thebent side l2, it will pass in between the electrodes l5 and Hi.

In carrying out my invention by the apparatus shown, the alternate links are fed'to the position shown in Figs. 4, 5, and-6 by means of the feed wheel 20. When they are in position, the holding plungers are brought into engagement with the ends ID of the link which serve to main- 4 tain it in position. Simultaneously with the actuation of the holding plungers or slightly thereafter, the electrodes l5 and I6 are brought into engagement and firm contact with the sides of the link at points near the ends of the straight side portion I l Electricity is now caused toflow through the electrodes by any suitable means (not shown) and the metal in the straight side H, between the, electrode is heated in well known manner. When the metal has reached the desired forging temperature, the bending tool 25 is brought down into engagement with the straight side H and with the side portions 21 straddling the side of the link. The curved working surface 25 will thus be brought into engagement with the side II and suitable force applied thereto through suitable cam means (not shown) to cause the heated metal in the sides II to be forced downwardly and formed into the bent sides l2 of the link.

It will be clear from Figs. 5 and 6 that each alternate link is acted upon on one of its sides as it passes into and through the apparatus used for heating and bending, the intermediate links being acted upon either by being repeatedly passed through the same apparatus or by being passed through another heating and bending apparatus. If, as disclosed in this application, each straight side II of the link is bentseparately, then the links will have to be passed again through the apparatus to bend the opposite sides.

While I have shown and described the bending of only one of the straight sides ll of the link at a time, it is obvious that a slightly modified apparatus might be employed whereby both straight sides of the link might be heated simultaneously and both sides simultaneously bent, my invention being of such a scope as to include such a modification.

Having thus described my invention, what I claim is:

1. A method of forming chain links for use in the treatment of wet slurry, comprising holding the link by endwise pressure, heating one of, the sides thereof by the application to such side of oppositely arranged electrodes, and bending the'side of the link inwardly toward the lonthereof, heating one of the sides of the link by' the application to such side of oppositely arranged electrodes, and bending the side thereof inwardly toward the longitudinal axis thereof while hot by exerting pressure which is independent of the holding pressure. s

3. A method of forming chain links for use in the treatment of wet slurry, comprising the support of assembled links upon an intermittently moving feed wheel, holdingthe link upon the wheel by endwise pressure, heating one of the sides thereof by the application to such side of oppositely arranged electrodes, and bending the side of the link inwardly toward the longitudinal axis thereof while hot by exerting pressure which is independent of the holding pressure.

4. A method of forming chain links for use in the treatment of wet slurry, comprising holding the link by endwise pressure, exerted above the longitudinal axis of the link and at opposite ends thereof, heating one of the sides of the link by the application to such side of oppositely arranged electrodes, and bending the side of the, link inwardly toward the longitudinal axis thereof while hot by exerting pressure by means substantially enveloping three sides of the'heated portion. of the link, whereby the cross-sectional shape of the heated side will be maintained.

5. A method of forming chain links for use in the treatment of wet slurry, comprising holding the link byendwise pressure, exerted above the longitudinal axis of the link and at opposite ends thereof, heating one of the sides of the link by the application to such side ofv oppositely arranged electrodes and at a position intermediate its length, then bending such heated side, then heating the opposite side at substantially the same place in its length, and then bending the last mentioned side.

6. A method of forming the links of an as-' sembled chain for use in the treatment of wet slurry, comprising heating one of the sides of one of the links at a position intermediate its length, then bending such heated side inwardly toward the center of the link, successively heating the corresponding side of each successive alternate link, then successively bendingsuch side of each successive alternate link inwardly toward the center of such link, then heating the opposite side of one of the links which has one of its sides already bent, then bending this side, then suc cessively heating the corresponding opposite side of each successive alternate link, and then successively bending the last mentioned side of each successive alternate link.

'7. A method of forming the links of an assembled chain for use in the treatment of wet slurry, comprising heating one of the sides of one of the links at a position intermediate its length, then bending such heated side inwardly toward the center of the link, successively heating the corresponding side of each successive alternate link, then successively bending such side of each successive alternate link inwardly toward the center of such link, then heating the opposite side of one of the links which has one of its sides already bent, then bending this side, then successively heating the corresponding opposite side of each successive alternate link, then successively bending the last mentioned side of each successive alternate link, then successively heating one side of each of the untreated links intermediate the alternate links, then successively bending such heated sides, then successively heating the opposite sides of the intermediate links, and then successively bending such heated opposite sides.

FRANK E. STAHL. 

